Food Farming A griculture
Lecture: Professor Webb returns next week!
Lab:
Exploring an Environmental Issue
– continue to work in
groups, bring together various delegated individual tasks (from
proposal), advance overall project, ask questions
FOOD
A griculture: Yield –
Varieties
Pest Control
Soil
Water
Fertilizer
A griculture: Energy
Supply of land for agriculture use is
limited
In 2011, 1.5 billion hectares are already under cultivation
Or, 3.7065x109 acres
This number is projected to increase over the next 50 years, especially in developing nations with less stable food production
AGRICULTURE: LAND
AGRICULTURE: LAND
The Millennium Ecosystem Assessment:
- Commissioned by UN Secretary General Annan in 2000
- Goal: To assess the consequences of ecosystem change for human well-being and the scientific basis for action
needed to enhance the conservation and sustainable use of those systems and their contribution to human well-being
In the past 50 years,
humans have
changed ecosystems
more rapidly and
extensively than in
any comparable
period of time in
human history
- M i l l e n n i u m E c o s y s t e m A s s e s s m e n t
M o r e l a n d w a s c o n v e r t e d to c r o p l a n d i n t h e 3 0 ye a r s a f t e r 1 9 5 0 t h a n i n t h e 1 5 0 ye a r s b e t w e e n 17 0 0 a n d 1 8 5 0
C u l t i v a t e d s y s t e m s c o v e r 2 5 % o f E a r t h ’ s t e r r e s t r i a l
s u r f a c e
Agriculture: Land
A griculture: Energy
Green Revolution
A griculture: Subsidies
A griculture: Climate Change
Organic Farming and Beyond
With less and less land
available for food
production, there is
pressure to
intensify
But there are competing
goals of multifunctional
agriculture
AGRICULTURE: YIELD
Avoid farming marginal lands
Restore grasslands on steeper slopes
Restore wetlands for water quality improvement
Allow for 100-300
f t
riparian stream buf fers
Increase crop diversity
5-year crop rotations
Row crops planted with cover crops
Managed intensive rotational grazing
B o o d y e t a l . 2 0 0 5 B i o S c i . Vo l . 5 5 ( 1 ) ; 27 - 3 8
AGRICULTURE: YIELD
COMPETING GOALS
Te r r a c e d A g r i c u l t u r e
C o m m o n i n A s i a
E r o s i o n
We t l a n d s
p r o v i d e h u m a n s w i t h n a t u r a l w a t e r
p u r i f i c a t i o n
H a b i t a t f o r r a r e s p e c i e s
P o o r l a n d f o r a g r i c u l t u r e ( l o w y i e l d )
G o o d to i n c o r p o r a t e p r e s e r v e d w e t l a n d s w i t h b u f f e r z o n e
RESTORE
WETLANDS
Wetland that was farmed upon then abandoned
P l a n t s p e c i e s a f f e c t s o i l c o m p o s i t i o n d i f f e r e n t l y
R o t a t e w h a t yo u p l a n t to l e t s o i l s r e j u v e n a t e
L o t s o f
t e c h n i q u e s – n e e d to k n o w w h a t k i n d o f s o i l yo u ’ r e w o r k i n g w i t h
CROP
L e s s i n te n s e d i r e c t s u n l i g h t
C o v e r e d c r o p s r e q u i r e l e s s f r e q u e n t w a t e r i n g s
M a n a g e s o i l f e r t i l i t y
M i t i g a t e p e s t s , d i s e a s e s ,
w e e d s , e r o s i o n o f s o i l s
IMPLEMENT
COVER
R o t a t i o n o f a n i m a l s to a l l o w f o r r e g r o w t h
C a n b e u s e d w i t h c o w s , s h e e p , g o a t s , p i g s , c h i c k e n s , d u c k s
S o m e f a r m e r s h a v e t e m p o r a r y f e n c e s
CAFO –
Concentrated Animal
Feeding Operation
Animal feeding facility
with no natural
vegetation (feed)
Animals grow
(fattened) in confined
space for > 6 weeks
Increase in yield
AGRICULTURE: YIELD
ENVIRONMENTAL IMPACTS OF CAFO
SPoint-source pollution from CAFO
Europe and US –
concerns for animal
welfare
Developing markets –
less/no concern
Unlikely to meet
global meat demand
without CAFOs
(TechnoGarden
scenario, MEA)
AGRICULTURE: YIELD
https://www.youtube.com/watch?v=-LjW6eIFYpo
A happier alternative (for the animals AND environment):
https://www.youtube.com/watch?v=z9HF93LfBDw
Visit Niman Ranch website for more information:
http://www.nimanranch.com/Index.aspx
AGRICULTURE: LAND
Yield = biomass achieved per unit area
Wheat:
11,032 pounds/acre – best modern plants, best fertilizer, best husbandry
5,511 pounds/acre – best yield from 1970s after Green Revolution
2,755 pounds/acre – typical practices in Argentina and India
There are two sources of increasing crop yield without
increasing amount of land used:
1) Increase in cropping intensities
Shorter fallow periods
2) Modify system through increased inputs
More biomass via increased nutrient inputs, denser plantings
WHICH OF THESE COULD POTENTIALLY HAVE AN ECOLOGICAL ISSUE ASSOCITED WITH ITS IMPLEMENTATION?
Yield depends on:
Crop/livestock variety – species and traits
New varieties generated through selective breeding, genetically modified organisms, and pests
Soil
Micro-organisms in soil biomass > dirt biomass
Water
Up to 80% may be wasted. Often subsidized. Over-watering water-logs soils. Agricultural Runoff.
Fertilizer
Responsible for > 50% of doubling of crop production in last 50 years. Over fertilization leads to aquatic ecosystem pollution.
Until recently there
were numerous
varieties from selective
breeding by humans
Selective breeding of
battery chickens
reduced input food
requirement from 4kg
of food/kg of eggs to
just 2kg food/kg eggs!
Turkeys so bloated they
cannot walk. Chickens
grow so fast they suffer
stress fractures.
PROS
Accelerates genetic
modification by faster
selection for desired
traits
Insertion of novel
genes
Increases yield,
resistance to
pathogens, ability to
process fertilizers,
freeze resistance
CONS
Accelerates
development of pest
resistance
Higher herbicide use for
GMO high tolerance
varieties
Reduce survival/growth
and diversity of wildlife
Gene jumping
Dilution of wild genome
and genetic diversity
AGRICULTURE: YIELD
GENETICALLY MODIFIED ORGANISMS
Ethical concerns:
Are we tampering with
nature?
Where’s the stopping
point?
Lots of information out
there on this topic –
know what you’re
reading!
AGRICULTURE: YIELD
Direct advantage
– increase yield by killing competitors
(pests)
Disadvantages
–
Pesticide resistance and pest resurgence (pesticide treadmill)
Non-target species: 90% misses
New pests
Bioaccumulation (Rachel Carson, Silent Spring)
“But man is a part of nature, and his war against nature is inevitably a war against himself.” – Rachel Carson
Farming Practices:
Crop rotation
Green manure
Natural, organic fertilizers
Polyculture
Vary planting times
Burning before planting
Flooding before planting
Surrounding habitat diversity
AGRICULTURE: YIELD
ALTERNATIVES TO PESTICIDES?
Biological Control
Predators, pathogens attack pests
Interplanting with pest deterrents
Sterile males/females
Sex attractants to traps
Integrated Pest Management
Organic Farming
AGRICULTURE YIELD:
ALTERNATIVES TO PESTICIDES?
> 1 5 , 0 0 0 s o i l t y p e s i n U S
A c c r u e 1 0 to n s / a c r e , ye a r
E r o s i o n < 2 5 m m / y e a r
AG R I C U LT U R E :
YIELD
Soil is easily exhausted by intensive agriculture
Loss of organic matter requires 5-10 years to recover
Low organic-matter soils lef t fallow for
8-10 years to recover
Loss of top-soil takes centuries to replace
Withdrawal –
water diver ted or withdrawn from a sur face
water or ground source that eventually returns to the system
Consumption –
water use that permanently draws water from
its source; water that is no longer available because it has
evaporated, has been consumed by humans or livestock , water
that has been removed from the immediate environment
Up to 80% of water can be wasted:
Often subsidized
Over-watering water-logs soils,
can promote salinization (build up of salts in soils, can be toxic, bad for future water uptake)
WATER
From the Webber reading: “More Food Less Energy”
A) Drip irrigation could save thousands of megawatt-hours of electricity nationwide every year.
B) Drip irrigation consists of long, narrow tubes placed at the tops of plants in order to water each plant locally with little loss to evaporation
C) Center-pivot sprinklers provides more crop per drop by spraying water into the air where a major fraction effectively waters crops
D) Drip irrigation consists of long, narrow tubes placed at the bottoms of plants in order to water each plant locally with little loss to evaporation
E) Both A and B
It takes ~ 132 gallons of water to produce 1 lb of cereal grain
~ 5,679 gallons/lb of beef
90% of infectious diseases in developing countries
transmitted by polluted water (of ten from agriculture)
This is going to become a big problem when agricultural system expand in these nations
Water footprint:
http://environment.nationalgeographic.com/environment/
freshwater/change-the-course/water-footprint-calculator/
Solutions?
Drip-feeding can reduce water usage by 40%, which increases overall yield (READ MORE FOOD LESS ENERGY)
No-till agriculture reduces water loss through evaporation and run-off, and also reduces soil temperature about 1°C (offset global warming)
Carbon sequestration – holds organic material underground and isn’t lost to the atmosphere
Save tilling time – grow extra crop in some countries
Less erosion of top soil
Flows of biologically
available
N
in terrestrial
ecosystems have
doubled since 1960
(flows of
P
have tripled)
>50% of all synthetic
N
fertilizer ever used has
been used since 1985
60% increase in the
atmospheric
concentration of
CO2
since 1750 has taken
place since 1959
What’s happening?
Plants also need
phosphorus in small
amounts, but these
elements are also
limiting
Effects of runoff with
nutrient loads of
N
&
P
DEAD ZONES
AGRICULTURE: YIELD
FERTILIZER
Gulf of Mexico Case Study
https://www.youtube.com/watch?v=ahOmeTOIrRg
Over-fer tilization
Produces “yield insurance”, add more to ensure maximum current yield
Excess enters water table – “Blue baby alerts” in Iowa
Salinization
Toxic
Soils untenable
Dead Zones
Hypoxia – excessive O2 demand
Eutrophication – nutrients are single biggest water quality problem worldwide (Carpenter et al., Ecol App 1998)
Non-functioning ecosystem
Alternatives?
Animal manure
Interplanting (legumes = N fixers)
Crop rotation
Green manure
Alternatives?
Use animal waste as fertilizer/soil improvement
Interstate regulations limit the transport of wastes and toxic material
Would reduce odor, dust, and escape of waste into system
Agriculture:
Agriculture: Yield
UM Sustainable Food Program
Which of the following is an example of direct energy use
involved in the processing and distribution of farm products?
A.
The manufacturing of fer tilizer
B.
Storage of the products
C.
Running the farm machiner y
to har vest the products
D.
Cooking the food
E.
Eating the products
Energy is another raw material used for farming
Two types of use:
Direct
Indirect
Another Raw Material for Farming -
Energy
Fossil fuel – key ingredient for increased global food production and distribution.
Direct use that is going to become more and more expensive as oil becomes a very limited resource!
“The U.S. expends roughly 10 units of fossil energy to produce one unit of food energy.” -Webber 2012. More Food, Less Energy. Scientific
American Jan, pp. 74-79
DIRECT USE
Operating machinery
Lights, and heating on
the farm
INDIRECT USE
Fertilizer manufacturer
Pesticide
manufacturer
Storage
Cooking
Distribution
